bsd/kern/kpi_socketfilter.c

   1 /*
   2  * Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22
  23 #include <sys/kpi_socketfilter.h>
  24
  25 #include <sys/socket.h>
  26 #include <sys/param.h>
  27 #include <sys/errno.h>
  28 #include <sys/malloc.h>
  29 #include <sys/protosw.h>
  30 #include <kern/locks.h>
  31 #include <net/kext_net.h>
  32
  33 static struct socket_filter_list        sock_filter_head;
  34 static lck_mtx_t                                        *sock_filter_lock = 0;
  35
  36 __private_extern__ void
  37 sflt_init(void)
  38 {
  39         lck_grp_attr_t  *grp_attrib = 0;
  40         lck_attr_t              *lck_attrib = 0;
  41         lck_grp_t               *lck_group = 0;
  42
  43         TAILQ_INIT(&sock_filter_head);
  44
  45         /* Allocate a spin lock */
  46         grp_attrib = lck_grp_attr_alloc_init();
  47         lck_grp_attr_setdefault(grp_attrib);
  48         lck_group = lck_grp_alloc_init("socket filter lock", grp_attrib);
  49         lck_grp_attr_free(grp_attrib);
  50         lck_attrib = lck_attr_alloc_init();
  51         lck_attr_setdefault(lck_attrib);
  52         lck_attr_setdebug(lck_attrib);
  53         sock_filter_lock = lck_mtx_alloc_init(lck_group, lck_attrib);
  54         lck_grp_free(lck_group);
  55         lck_attr_free(lck_attrib);
  56 }
  57
  58 __private_extern__ void
  59 sflt_initsock(
  60         struct socket *so)
  61 {
  62         struct protosw *proto = so->so_proto;
  63         struct socket_filter *filter;
  64
  65         if (TAILQ_FIRST(&proto->pr_filter_head) != NULL) {
  66                 lck_mtx_lock(sock_filter_lock);
  67                 TAILQ_FOREACH(filter, &proto->pr_filter_head, sf_protosw_next) {
  68                         sflt_attach_private(so, filter, 0, 0);
  69                 }
  70                 lck_mtx_unlock(sock_filter_lock);
  71         }
  72 }
  73
  74 __private_extern__ void
  75 sflt_termsock(
  76         struct socket *so)
  77 {
  78         struct socket_filter_entry *filter;
  79         struct socket_filter_entry *filter_next;
  80
  81         for (filter = so->so_filt; filter; filter = filter_next) {
  82                 filter_next = filter->sfe_next_onsocket;
  83                 sflt_detach_private(filter, 0);
  84         }
  85 }
  86
  87 __private_extern__ void
  88 sflt_use(
  89         struct socket *so)
  90 {
  91         so->so_filteruse++;
  92 }
  93
  94 __private_extern__ void
  95 sflt_unuse(
  96         struct socket *so)
  97 {
  98         so->so_filteruse--;
  99         if (so->so_filteruse == 0) {
 100                 struct socket_filter_entry *filter;
 101                 struct socket_filter_entry *next_filter;
 102                 // search for detaching filters
 103                 for (filter = so->so_filt; filter; filter = next_filter) {
 104                         next_filter = filter->sfe_next_onsocket;
 105
 106                         if (filter->sfe_flags & SFEF_DETACHING) {
 107                                 sflt_detach_private(filter, 0);
 108                         }
 109                 }
 110         }
 111 }
 112
 113 __private_extern__ void
 114 sflt_notify(
 115         struct socket   *so,
 116         sflt_event_t    event,
 117         void                    *param)
 118 {
 119         struct socket_filter_entry      *filter;
 120         int                                                     filtered = 0;
 121
 122         for (filter = so->so_filt; filter;
 123                  filter = filter->sfe_next_onsocket) {
 124                 if (filter->sfe_filter->sf_filter.sf_notify) {
 125                         if (filtered == 0) {
 126                                 filtered = 1;
 127                                 sflt_use(so);
 128                                 socket_unlock(so, 0);
 129                         }
 130                         filter->sfe_filter->sf_filter.sf_notify(
 131                                 filter->sfe_cookie, so, event, param);
 132                 }
 133         }
 134
 135         if (filtered != 0) {
 136                 socket_lock(so, 0);
 137                 sflt_unuse(so);
 138         }
 139 }
 140
 141 __private_extern__ int
 142 sflt_data_in(
 143         struct socket                   *so,
 144         const struct sockaddr   *from,
 145         mbuf_t                                  *data,
 146         mbuf_t                                  *control,
 147         sflt_data_flag_t                flags)
 148 {
 149         struct socket_filter_entry      *filter;
 150         int                                                     filtered = 0;
 151         int                                                     error = 0;
 152
 153         for (filter = so->so_filt; filter && (error == 0);
 154                  filter = filter->sfe_next_onsocket) {
 155                 if (filter->sfe_filter->sf_filter.sf_data_in) {
 156                         if (filtered == 0) {
 157                                 filtered = 1;
 158                                 sflt_use(so);
 159                                 socket_unlock(so, 0);
 160                         }
 161                         error = filter->sfe_filter->sf_filter.sf_data_in(
 162                                                 filter->sfe_cookie, so, from, data, control, flags);
 163                 }
 164         }
 165
 166         if (filtered != 0) {
 167                 socket_lock(so, 0);
 168                 sflt_unuse(so);
 169         }
 170
 171         return error;
 172 }
 173
 174 /* sflt_attach_private
 175  *
 176  * Assumptions: If filter is not NULL, socket_filter_lock is held.
 177  */
 178
 179 __private_extern__ int
 180 sflt_attach_private(
 181         struct socket *so,
 182         struct socket_filter *filter,
 183         sflt_handle                     handle,
 184         int sock_locked)
 185 {
 186         struct socket_filter_entry *entry = NULL;
 187         int didlock = 0;
 188         int error = 0;
 189
 190         if (filter == NULL) {
 191                 /* Find the filter by the handle */
 192                 lck_mtx_lock(sock_filter_lock);
 193                 didlock = 1;
 194
 195                 TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 196                         if (filter->sf_filter.sf_handle == handle)
 197                                 break;
 198                 }
 199         }
 200
 201         if (filter == NULL)
 202                 error = ENOENT;
 203
 204         if (error == 0) {
 205                 /* allocate the socket filter entry */
 206                 MALLOC(entry, struct socket_filter_entry *, sizeof(*entry), M_IFADDR, M_WAITOK);
 207                 if (entry == NULL) {
 208                         error = ENOMEM;
 209                 }
 210         }
 211
 212         if (error == 0) {
 213                 /* Initialize the socket filter entry and call the attach function */
 214                 entry->sfe_filter = filter;
 215                 entry->sfe_socket = so;
 216                 entry->sfe_cookie = NULL;
 217                 if (entry->sfe_filter->sf_filter.sf_attach) {
 218                         filter->sf_usecount++;
 219
 220                         if (sock_locked)
 221                                 socket_unlock(so, 0);
 222                         error = entry->sfe_filter->sf_filter.sf_attach(&entry->sfe_cookie, so);
 223                         if (sock_locked)
 224                                 socket_lock(so, 0);
 225
 226                         filter->sf_usecount--;
 227
 228                         /* If the attach function returns an error, this filter is not attached */
 229                         if (error) {
 230                                 FREE(entry, M_IFADDR);
 231                                 entry = NULL;
 232                         }
 233                 }
 234         }
 235
 236         if (error == 0) {
 237                 /* Put the entry in the socket list */
 238                 entry->sfe_next_onsocket = so->so_filt;
 239                 so->so_filt = entry;
 240
 241                 /* Put the entry in the filter list */
 242                 entry->sfe_next_onfilter = filter->sf_entry_head;
 243                 filter->sf_entry_head = entry;
 244
 245                 /* Increment the socket's usecount */
 246                 so->so_usecount++;
 247
 248                 /* Incremenet the parent filter's usecount */
 249                 filter->sf_usecount++;
 250         }
 251
 252         if (didlock) {
 253                 lck_mtx_unlock(sock_filter_lock);
 254         }
 255
 256         return error;
 257 }
 258
 259
 260 /* sflt_detach_private
 261  *
 262  * Assumptions: if you pass 0 in for the second parameter, you are holding the
 263  * socket lock for the socket the entry is attached to. If you pass 1 in for
 264  * the second parameter, it is assumed that the entry is not on the filter's
 265  * list and the socket lock is not held.
 266  */
 267
 268 __private_extern__ void
 269 sflt_detach_private(
 270         struct socket_filter_entry *entry,
 271         int     filter_detached)
 272 {
 273         struct socket *so = entry->sfe_socket;
 274         struct socket_filter_entry **next_ptr;
 275         int                             detached = 0;
 276         int                             found = 0;
 277
 278         if (filter_detached) {
 279                 socket_lock(entry->sfe_socket, 0);
 280         }
 281
 282         /*
 283          * Attempt to find the entry on the filter's list and
 284          * remove it. This prevents a filter detaching at the
 285          * same time from attempting to remove the same entry.
 286          */
 287         lck_mtx_lock(sock_filter_lock);
 288         if (!filter_detached) {
 289                 for (next_ptr = &entry->sfe_filter->sf_entry_head; *next_ptr;
 290                          next_ptr = &((*next_ptr)->sfe_next_onfilter)) {
 291                         if (*next_ptr == entry) {
 292                                 found = 1;
 293                                 *next_ptr = entry->sfe_next_onfilter;
 294                                 break;
 295                         }
 296                 }
 297         }
 298
 299         if (!filter_detached && !found && (entry->sfe_flags & SFEF_DETACHING) == 0) {
 300                 lck_mtx_unlock(sock_filter_lock);
 301                 return;
 302         }
 303
 304         if (entry->sfe_socket->so_filteruse != 0) {
 305                 lck_mtx_unlock(sock_filter_lock);
 306                 entry->sfe_flags |= SFEF_DETACHING;
 307                 return;
 308         }
 309
 310         /*
 311          * Check if we are removing the last attached filter and
 312          * the parent filter is being unregistered.
 313          */
 314         if (entry->sfe_socket->so_filteruse == 0) {
 315                 entry->sfe_filter->sf_usecount--;
 316                 if ((entry->sfe_filter->sf_usecount == 0) &&
 317                         (entry->sfe_filter->sf_flags & SFF_DETACHING) != 0)
 318                         detached = 1;
 319         }
 320         lck_mtx_unlock(sock_filter_lock);
 321
 322         /* Remove from the socket list */
 323         for (next_ptr = &entry->sfe_socket->so_filt; *next_ptr;
 324                  next_ptr = &((*next_ptr)->sfe_next_onsocket)) {
 325                 if (*next_ptr == entry) {
 326                         *next_ptr = entry->sfe_next_onsocket;
 327                         break;
 328                 }
 329         }
 330
 331         if (entry->sfe_filter->sf_filter.sf_detach)
 332                 entry->sfe_filter->sf_filter.sf_detach(entry->sfe_cookie, entry->sfe_socket);
 333
 334         if (detached && entry->sfe_filter->sf_filter.sf_unregistered) {
 335                 entry->sfe_filter->sf_filter.sf_unregistered(entry->sfe_filter->sf_filter.sf_handle);
 336                 FREE(entry->sfe_filter, M_IFADDR);
 337         }
 338
 339         if (filter_detached) {
 340                 socket_unlock(entry->sfe_socket, 1);
 341         }
 342         else {
 343                 // We need some better way to decrement the usecount
 344                 so->so_usecount--;
 345         }
 346         FREE(entry, M_IFADDR);
 347 }
 348
 349 errno_t
 350 sflt_attach(
 351         socket_t        socket,
 352         sflt_handle     handle)
 353 {
 354         if (socket == NULL || handle == 0)
 355                 return EINVAL;
 356
 357         return sflt_attach_private(socket, NULL, handle, 0);
 358 }
 359
 360 errno_t
 361 sflt_detach(
 362         socket_t        socket,
 363         sflt_handle     handle)
 364 {
 365         struct socket_filter_entry      *filter;
 366         errno_t result = 0;
 367
 368         if (socket == NULL || handle == 0)
 369                 return EINVAL;
 370
 371         socket_lock(socket, 1);
 372
 373         for (filter = socket->so_filt; filter;
 374                  filter = filter->sfe_next_onsocket) {
 375                 if (filter->sfe_filter->sf_filter.sf_handle == handle)
 376                         break;
 377         }
 378
 379         if (filter != NULL) {
 380                 sflt_detach_private(filter, 0);
 381         }
 382         else {
 383                 result = ENOENT;
 384         }
 385
 386         socket_unlock(socket, 1);
 387
 388         return result;
 389 }
 390
 391
 392 errno_t
 393 sflt_register(
 394         const struct sflt_filter        *filter,
 395         int                                                     domain,
 396         int                                                     type,
 397         int                                                     protocol)
 398 {
 399         struct socket_filter *sock_filt = NULL;
 400         struct socket_filter *match = NULL;
 401         int error = 0;
 402         struct protosw *pr = pffindproto(domain, protocol, type);
 403
 404         if (pr == NULL) return ENOENT;
 405
 406         if (filter->sf_attach == NULL || filter->sf_detach == NULL) return EINVAL;
 407         if (filter->sf_handle == 0) return EINVAL;
 408         if (filter->sf_name == NULL) return EINVAL;
 409
 410         /* Allocate the socket filter */
 411         MALLOC(sock_filt, struct socket_filter*, sizeof(*sock_filt), M_IFADDR, M_WAITOK);
 412         if (sock_filt == NULL) {
 413                 return ENOBUFS;
 414         }
 415
 416         bzero(sock_filt, sizeof(*sock_filt));
 417         sock_filt->sf_filter = *filter;
 418
 419         lck_mtx_lock(sock_filter_lock);
 420         /* Look for an existing entry */
 421         TAILQ_FOREACH(match, &sock_filter_head, sf_global_next) {
 422                 if (match->sf_filter.sf_handle == sock_filt->sf_filter.sf_handle) {
 423                         break;
 424                 }
 425         }
 426
 427         /* Add the entry only if there was no existing entry */
 428         if (match == NULL) {
 429                 TAILQ_INSERT_TAIL(&sock_filter_head, sock_filt, sf_global_next);
 430                 if ((sock_filt->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 431                         TAILQ_INSERT_TAIL(&pr->pr_filter_head, sock_filt, sf_protosw_next);
 432                         sock_filt->sf_proto = pr;
 433                 }
 434         }
 435         lck_mtx_unlock(sock_filter_lock);
 436
 437         if (match != NULL) {
 438                 FREE(sock_filt, M_IFADDR);
 439                 return EEXIST;
 440         }
 441
 442         return error;
 443 }
 444
 445 errno_t
 446 sflt_unregister(
 447         sflt_handle handle)
 448 {
 449         struct socket_filter *filter;
 450         struct socket_filter_entry *entry_head = NULL;
 451
 452         /* Find the entry and remove it from the global and protosw lists */
 453         lck_mtx_lock(sock_filter_lock);
 454         TAILQ_FOREACH(filter, &sock_filter_head, sf_global_next) {
 455                 if (filter->sf_filter.sf_handle == handle)
 456                         break;
 457         }
 458
 459         if (filter) {
 460                 TAILQ_REMOVE(&sock_filter_head, filter, sf_global_next);
 461                 if ((filter->sf_filter.sf_flags & SFLT_GLOBAL) != 0) {
 462                         TAILQ_REMOVE(&filter->sf_proto->pr_filter_head, filter, sf_protosw_next);
 463                 }
 464                 entry_head = filter->sf_entry_head;
 465                 filter->sf_entry_head = NULL;
 466                 filter->sf_flags |= SFF_DETACHING;
 467         }
 468
 469         lck_mtx_unlock(sock_filter_lock);
 470
 471         if (filter == NULL)
 472                 return ENOENT;
 473
 474         /* We need to detach the filter from any sockets it's attached to */
 475         if (entry_head == 0) {
 476                 if (filter->sf_filter.sf_unregistered)
 477                         filter->sf_filter.sf_unregistered(filter->sf_filter.sf_handle);
 478         } else {
 479                 while (entry_head) {
 480                         struct socket_filter_entry *next_entry;
 481                         next_entry = entry_head->sfe_next_onfilter;
 482                         sflt_detach_private(entry_head, 1);
 483                         entry_head = next_entry;
 484                 }
 485         }
 486
 487         return 0;
 488 }
 489
 490 errno_t
 491 sock_inject_data_in(
 492         socket_t so,
 493         const struct sockaddr* from,
 494         mbuf_t data,
 495         mbuf_t control,
 496         sflt_data_flag_t flags)
 497 {
 498         int error = 0;
 499         if (so == NULL || data == NULL) return EINVAL;
 500
 501         if (flags & sock_data_filt_flag_oob) {
 502                 return ENOTSUP;
 503         }
 504
 505         socket_lock(so, 1);
 506
 507         if (from) {
 508                 if (sbappendaddr(&so->so_rcv, (struct sockaddr*)from, data,
 509                                                  control, NULL))
 510                         sorwakeup(so);
 511                 goto done;
 512         }
 513
 514         if (control) {
 515                 if (sbappendcontrol(&so->so_rcv, data, control, NULL))
 516                         sorwakeup(so);
 517                 goto done;
 518         }
 519
 520         if (flags & sock_data_filt_flag_record) {
 521                 if (control || from) {
 522                         error = EINVAL;
 523                         goto done;
 524                 }
 525                 if (sbappendrecord(&so->so_rcv, (struct mbuf*)data))
 526                         sorwakeup(so);
 527                 goto done;
 528         }
 529
 530         if (sbappend(&so->so_rcv, data))
 531                 sorwakeup(so);
 532 done:
 533         socket_unlock(so, 1);
 534         return error;
 535 }
 536
 537 errno_t
 538 sock_inject_data_out(
 539         socket_t so,
 540         const struct sockaddr* to,
 541         mbuf_t data,
 542         mbuf_t control,
 543         sflt_data_flag_t flags)
 544 {
 545         int     sosendflags = 0;
 546         if (flags & sock_data_filt_flag_oob) sosendflags = MSG_OOB;
 547         return sosend(so, (const struct sockaddr*)to, NULL,
 548                                   data, control, sosendflags);
 549 }
 550
 551 sockopt_dir
 552 sockopt_direction(
 553         sockopt_t       sopt)
 554 {
 555         return (sopt->sopt_dir == SOPT_GET) ? sockopt_get : sockopt_set;
 556 }
 557
 558 int
 559 sockopt_level(
 560         sockopt_t       sopt)
 561 {
 562         return sopt->sopt_level;
 563 }
 564
 565 int
 566 sockopt_name(
 567         sockopt_t       sopt)
 568 {
 569         return sopt->sopt_name;
 570 }
 571
 572 size_t
 573 sockopt_valsize(
 574         sockopt_t       sopt)
 575 {
 576         return sopt->sopt_valsize;
 577 }
 578
 579 errno_t
 580 sockopt_copyin(
 581         sockopt_t       sopt,
 582         void *data,
 583         size_t  len)
 584 {
 585         return sooptcopyin(sopt, data, len, len);
 586 }
 587
 588 errno_t
 589 sockopt_copyout(
 590         sockopt_t       sopt,
 591         void *data,
 592         size_t  len)
 593 {
 594         return sooptcopyout(sopt, data, len);
 595 }